Device and method for testing explosive power of lithium ion battery

Abstract

The invention discloses a lithium ion battery explosive power testing device and method. The testing device comprises an anti-explosion tank, a functional material, a thermal runaway triggering unit, a shock wave overpressure testing unit, an optical testing unit and an explosion noise testing unit. The functional material is laid on the inner wall of the anti-explosion tank and has the functions of heat insulation, flame retardance, sound absorption and wave absorption; a lithium ion battery to be tested is arranged in the anti-explosion tank; the thermal runaway triggering unit is used for triggering thermal runaway of the lithium ion battery to explode; the shock wave overpressure test unit is used for measuring a shock wave pressure curve after the battery explodes; the optical test unit is used for measuring luminous intensity and temperature after the battery explodes; the explosion noise test unit is located above the lithium ion battery to be tested and is used for measuring the sound intensity generated by battery explosion. According to the invention, the explosive power of the battery after thermal runaway can be comprehensively evaluated through a multi-dimensional test means.

Description

Technical Field

[0001] The present invention relates to the technical field of safety testing of lithium - ion batteries, and particularly to a device and method for testing the explosion power of lithium - ion batteries. Background Art

[0002] With the large - scale application of lithium - ion batteries in fields such as electric vehicles and energy storage systems, their safety issues, especially the explosion incidents that may be triggered after battery thermal runaway, have become the focus of the industry. Thermal runaway not only causes the battery to emit smoke and catch fire, but may also release huge energy in a very short time, generating strong shock waves and photothermal radiation, posing a serious threat to the surrounding environment and personnel. Therefore, accurately quantifying and evaluating the explosion power of the battery is of great significance for improving the safety performance of the battery and the battery system.

[0003] In the prior art, the testing methods for the explosion power of lithium - ion batteries are relatively single, mostly relying on pressure sensors to measure the shock wave pressure after the explosion, while ignoring the complexity of the testing environment and the multi - dimensional characteristics of the explosion hazards, such as photothermal radiation and sound intensity, and it is difficult to comprehensively reflect the actual hazards of battery explosion. Summary of the Invention

[0004] In view of this, the present invention provides a device and method for testing the explosion power of lithium - ion batteries, which can comprehensively evaluate the explosion power after battery thermal runaway through multi - dimensional testing means.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A device for testing the explosion power of lithium - ion batteries includes an explosion - proof tank, functional materials, a thermal runaway trigger unit, a shock wave over - pressure testing unit, an optical testing unit, and an explosion noise testing unit;

[0007] The functional materials are laid on the inner wall of the explosion - proof tank and have the functions of heat insulation, flame retardancy, sound absorption, and wave absorption; the lithium - ion battery to be tested is placed in the explosion - proof tank; the thermal runaway trigger unit is used to trigger the thermal runaway and explosion of the lithium - ion battery; the shock wave over - pressure testing unit is used to measure the shock wave pressure curve after the battery explosion; the optical testing unit is used to measure the luminous intensity and temperature after the battery explosion; the explosion noise testing unit is located above the lithium - ion battery to be tested and is used to measure the sound intensity generated by the battery explosion.

[0008] Further, the thermal runaway trigger unit includes an over - charge trigger module, a thermal trigger module, and a pin - prick trigger module.

[0009] Further, the shock wave over - pressure testing unit includes n pressure sensors, where n≥1;

[0010] The optical test unit includes a flame photometers and b infrared camera probes, where a, b ≥ 1.

[0011] Further, n = 3, a = 3, and b = 3. A shock wave pressure sensor, a flame photometer, and an infrared camera probe are respectively arranged in three directions: perpendicular to the battery plate direction, parallel to the battery plate direction, and the vertical direction parallel to the battery plate direction.

[0012] Further, a protective cover is provided outside the infrared camera probe. The part corresponding to the lens of the infrared camera probe on the protective cover is glass, and the other parts are made of metal.

[0013] Further, the method for determining the thickness of the functional material is as follows:

[0014] Set the initial thickness of the functional material, measure the temperature, sound intensity, and light emission intensity during the battery explosion, and increase its thickness in gradients. Then, measure the temperature, sound intensity, and light emission intensity during the battery explosion again until the three measured parameters all fluctuate within a reasonable range. The thickness at this time is the optimal thickness;

[0015] If the optimal thickness exceeds 5 cm, it is necessary to replace the type of the functional material and retest to obtain the optimal thickness.

[0016] Further, the functional material is glass fiber cotton or rock wool-based material.

[0017] Further, the explosion-proof tank includes a cavity and an upper cover. The cavity is a hollow cylinder, and the upper cover is circular; both the cavity and the upper cover are made of stainless steel material, and the cavity and the upper cover are fixedly connected by explosion-proof bolts.

[0018] The present invention also provides a method for testing the explosion power of a lithium-ion battery. Using the above test device, the steps of the test method are as follows:

[0019] Step 1, fix the lithium-ion battery to be tested in the explosion-proof tank;

[0020] Step 2, turn on the shock wave overpressure test unit, the optical test unit, and the explosion noise test unit to make them enter the working mode;

[0021] Step 3, use the thermal runaway trigger unit to trigger the battery to have a thermal runaway, and record and save the shock wave pressure curve, light emission intensity, temperature, and sound intensity after the battery explosion;

[0022] Step 4, extract the maximum shock wave pressure, the maximum light emission intensity, the maximum temperature, and the maximum sound intensity, and record them as A, B, C, and D respectively;

[0023] Step 5: According to the requirements of the battery application scenario, the analytic hierarchy process is used to comprehensively evaluate the explosion hazard of the battery based on A, B, C, and D.

[0024] Further, in the above Step 5, the shock wave pressure, light intensity, temperature, and sound intensity are weighted and recorded as E, F, G, and H respectively, where E + F + G + H = 100%; define the battery explosion hazard index X, then X = A * E + B * F + C * G + D * H. The larger X is, the higher the comprehensive explosion hazard of the battery indicates.

[0025] Beneficial effects:

[0026] 1. Based on the complexity of the test environment and the multi-dimensional characteristics of the explosion hazard, the present invention adds the tests of the light intensity, temperature, and sound intensity of the lithium-ion battery, and can comprehensively and accurately evaluate the explosion power of the lithium-ion battery under thermal runaway conditions, providing strong support for improving the safety performance of the battery and the battery system.

[0027] 2. The thermal runaway trigger unit of the present invention includes an overcharge trigger module, a thermal trigger module, and a needle puncture trigger module, and can select the corresponding trigger module to trigger the battery thermal runaway according to the test needs, with high reliability.

[0028] 3. Since the battery explosion has a directionality, the present invention arranges pressure sensors, flame photometers, and infrared camera probes in three directions of the battery plate, and can more comprehensively test the shock wave pressure, light intensity, and temperature after the battery explodes.

[0029] 4. The analytic hierarchy process adopted by the present invention can clearly identify the importance of each factor and assign corresponding weights. By calculating the weights, the importance of each factor is accurately quantified, which is convenient for comparison and selection. By synthesizing the weights of each level, the overall evaluation result is obtained, improving the reliability and credibility of the result. Moreover, the parameters can be quickly adjusted or the importance of the factors can be re-evaluated, so as to adapt to dynamic decision-making needs, with strong adaptability. Description of the drawings

[0030] Figure 1 It is a schematic structural diagram of the test device of the present invention.

[0031] Among them, 10 - explosion-proof tank, 11 - functional material, 12 - lithium-ion battery to be tested, 13 - needle puncture trigger module, 14 - overcharge trigger module, 15 - thermal trigger module, 16 - optical test unit, 17 - shock wave overpressure test unit, 18 - explosion noise test unit. Detailed implementation manners

[0032] The following combines the drawings and gives examples to describe the present invention in detail.

[0033] The present invention provides a test device for the explosion power of a lithium-ion battery, as Figure 1 shown. The test device includes an explosion-proof tank 10, a functional material 11, a thermal runaway trigger unit, a shock wave overpressure test unit 17, an optical test unit 16, and an explosion noise test unit 18.

[0034] The functional material 11 is laid on the inner wall of the explosion-proof tank 10 and has the functions of heat insulation, flame retardancy, sound absorption, and wave absorption; the lithium-ion battery 12 to be tested is placed in the explosion-proof tank 10; the thermal runaway trigger unit is used to trigger the thermal runaway of the lithium-ion battery to cause an explosion; the shock wave overpressure test unit 17 is used to measure the shock wave pressure curve after the battery explodes; the optical test unit 16 is used to measure the light emission intensity and temperature after the battery explodes; the explosion noise test unit 18 is located above the lithium-ion battery 12 to be tested and is used to measure the sound intensity generated by the battery explosion.

[0035] Specifically, the explosion-proof tank 10 includes a cavity and an upper cover. The cavity is a hollow cylinder, and the upper cover is circular; both the cavity and the upper cover are made of stainless steel materials, and the cavity and the upper cover are fixedly connected by explosion-proof bolts.

[0036] The heat insulation function of the functional material 11 is to prevent the heat generated by the battery from dissipating and affecting the temperature measurement; the flame retardancy function is to prevent the functional material 11 from being ignited; the sound absorption function is to reduce the reflection and superposition of the battery explosion sound on the inner wall of the tank and affect the measurement accuracy of the explosion sound; the wave absorption function is to prevent the reflection and superposition of the battery explosion light emission intensity and affect the measurement accuracy of the light emission intensity. The functional material 11 can be glass fiber cotton or rock wool-based material.

[0037] On the one hand, the thickness of the functional material 11 cannot be too thin, otherwise the functions of heat insulation, sound absorption, and wave absorption are difficult to achieve; on the other hand, it cannot be too thick, otherwise it will occupy more space inside the cavity of the explosion-proof tank 10. Preferably, the thickness of the functional material 11 does not exceed 5 cm. The specific thickness determination method is as follows: set the initial thickness of the functional material 11, test the temperature, sound intensity, and light emission intensity during the battery explosion, and increase the thickness of the functional material 11 in gradients and test the temperature, sound intensity, and light emission intensity during the battery explosion again until the three measured parameters all fluctuate within a reasonable range (basically stable and unchanged), and the thickness at this time is the optimal thickness; if the optimal thickness is too large, such as exceeding 5 cm, consider replacing the material type and retesting to obtain the optimal thickness of the new material.

[0038] The thermal runaway trigger unit includes three trigger modules: an overcharge trigger module 14, a thermal trigger module 15, and a needle puncture trigger module 13; the overcharge trigger module 14 includes positive and negative power lines, a temperature sensor, and a charge and discharge device, and the charge and discharge device is connected to the lithium-ion battery 12 to be tested through the positive and negative power lines; the temperature sensor is electrically connected to the lithium-ion battery 12 to be tested and is used to test the temperature after the battery explosion.

[0039] The thermal trigger module 15 includes a ceramic heating sheet, a temperature sensor and an external power supply. The ceramic heating sheet is arranged on the lithium-ion battery 12 to be tested, and the external power supply is connected to the ceramic heating sheet through a cable; the temperature sensor is electrically connected to the lithium-ion battery 12 to be tested and is used to measure the temperature after the battery explodes.

[0040] The puncture trigger module 13 includes a puncture head, a hydraulic advancing device and a temperature sensor. The puncture head is arranged beside the lithium-ion battery 12 to be tested, and the hydraulic advancing device is used to drive the puncture head to move towards the lithium-ion battery 12 to be tested; the temperature sensor is electrically connected to the lithium-ion battery 12 to be tested and is used to measure the temperature after the battery explodes.

[0041] The shock wave overpressure test unit 17, the optical test unit 16 and the explosion noise test unit 18 are all arranged on the inner wall of the explosion-proof tank 10 after laying the functional material 11.

[0042] The shock wave overpressure test unit 17 includes n pressure sensors, where n≥1. Preferably, n = 3, and one shock wave pressure sensor is arranged in each of the three directions: the direction perpendicular to the battery plate (denoted as the X direction), the direction parallel to the battery plate (denoted as the Y direction), and the vertical direction parallel to the battery plate (denoted as the Z direction).

[0043] The optical test unit 16 includes a flame photometers and b infrared camera probes, where a, b≥1. Preferably, a = 3 and b = 3, and one flame photometer and one infrared camera probe are arranged in each of the three directions: the direction perpendicular to the battery plate, the direction parallel to the battery plate, and the vertical direction parallel to the battery plate. A protective cover is provided outside the infrared camera probe, and the part corresponding to the lens of the infrared camera probe is made of glass, and the other parts are made of metal.

[0044] The explosion noise test unit 18 uses a sound pressure meter to measure the sound intensity generated by the battery explosion by using the sound pressure test principle.

[0045] The present invention also provides a method for testing the explosion power of a lithium-ion battery. Using the above test device, the steps of the test method are as follows:

[0046] Step 1, fix the lithium-ion battery 12 to be tested in the explosion-proof tank 10;

[0047] Step 2, turn on the shock wave overpressure test unit 17, the optical test unit 16 and the explosion noise test unit 18 to make them enter the working mode;

[0048] Step 3, use the thermal runaway trigger unit to trigger the battery to have a thermal runaway, and record and save the shock wave pressure curve, light emission intensity, temperature, and sound intensity after the battery explodes;

[0049] Step 4: Extract the maximum values of shock wave pressure, light intensity, temperature, and sound intensity, denoted as A, B, C, and D respectively. The larger the value of A, the greater the harm of the battery explosion shock wave; the larger the value of B, the greater the harm of the battery explosion light intensity; the larger the value of C, the greater the harm of the battery explosion high temperature; the larger the value of D, the greater the harm of the battery explosion noise. By comparing the values of A, B, C, and D after different lithium battery explosions, the harm levels of shock wave, light intensity, high temperature, and noise after different lithium battery explosions can be compared respectively.

[0050] Step 5: According to the requirements of the battery application scenario, use the analytic hierarchy process to comprehensively evaluate the battery explosion hazard based on A, B, C, and D. Specifically, weight division is performed on shock wave pressure, light intensity, temperature, and sound intensity, denoted as E, F, G, and H respectively, and E + F + G + H = 100%; for example, if a certain scenario has higher requirements for shock wave pressure, lower requirements for light intensity, third for temperature, and the lowest requirements for sound intensity, then the weight ratio order of shock wave pressure, light intensity, temperature, and sound intensity is E > F > G > H. Define the battery explosion hazard index X, then X = A * E + B * F + C * G + D * H. The larger the value of X, the higher the comprehensive harm of the battery explosion.

[0051] In summary, the above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A test device for the explosion power of a lithium-ion battery, characterized in that It includes an explosion-proof tank, functional materials, a thermal runaway triggering unit, a shock wave overpressure testing unit, an optical testing unit, and an explosion noise testing unit; The functional materials are laid on the inner wall of the explosion-proof tank, having the functions of heat insulation, flame retardancy, sound absorption, and wave absorption; the lithium-ion battery to be tested is placed in the explosion-proof tank; the thermal runaway triggering unit is used to trigger the thermal runaway of the lithium-ion battery to cause an explosion; the shock wave overpressure testing unit is used to measure the shock wave pressure curve after the battery explosion; the optical testing unit is used to measure the light emission intensity and temperature after the battery explosion; the explosion noise testing unit is located above the lithium-ion battery to be tested and is used to measure the sound intensity generated by the battery explosion.

2. The lithium-ion battery explosion power test device according to claim 1, characterized in that, The thermal runaway triggering unit includes an overcharge triggering module, a thermal triggering module, and a needle puncture triggering module.

3. The lithium-ion battery explosion power test device according to claim 1, wherein, The shock wave overpressure testing unit includes n pressure sensors, where n≥1; The optical testing unit includes a flame photometers and b infrared camera probes, where a, b≥1.

4. The lithium-ion battery explosion power testing device according to claim 3, characterized in that When n = 3, a = 3, and b = 3, a shock wave pressure sensor, a flame photometer, and an infrared camera probe are respectively arranged in three directions: the direction perpendicular to the battery plate, the direction parallel to the battery plate, and the vertical direction parallel to the battery plate.

5. The lithium-ion battery explosion power testing device according to claim 3, wherein A protective cover is provided outside the infrared camera probe. The part corresponding to the lens of the infrared camera probe on the protective cover is glass, and the other parts are made of metal.

6. The lithium-ion battery explosion power testing device according to any one of claims 1-5, characterized in that, The method for determining the thickness of the functional materials is as follows: Set the initial thickness of the functional materials, test the temperature, sound intensity, and light emission intensity during the battery explosion, and increase its thickness in gradients, and then test the temperature, sound intensity, and light emission intensity during the battery explosion again until the three measured parameters all fluctuate within a reasonable range. At this time, the thickness is the optimal thickness; If the optimal thickness exceeds 5 cm, it is necessary to replace the type of the functional materials and retest to obtain the optimal thickness.

7. The lithium-ion battery explosion power testing device according to claim 6, characterized in that, The functional materials are glass fiber cotton or rock wool-based materials.

8. The lithium-ion battery explosion power testing device according to claim 6, wherein, The explosion-proof tank includes a cavity and an upper cover. The cavity is a hollow cylinder, and the upper cover is circular; both the cavity and the upper cover are made of stainless steel materials, and the cavity and the upper cover are fixedly connected by explosion-proof bolts.

9. A method for testing the explosion power of a lithium-ion battery, characterized in that, Using the testing device as described in claim 1, the testing method steps are as follows: Step 1, fix the lithium-ion battery to be tested in the explosion-proof tank; Step 2, turn on the shock wave overpressure testing unit, the optical testing unit, and the explosion noise testing unit to make them enter the working mode; Step 3, use the thermal runaway triggering unit to trigger the thermal runaway of the battery, and record and save the shock wave pressure curve, light emission intensity, temperature, and sound intensity after the battery explosion; Step 4, extract the maximum shock wave pressure, the maximum light emission intensity, the maximum temperature, and the maximum sound intensity, and record them as A, B, C, and D respectively; Step 5, according to the requirements of the battery application scenario, comprehensively evaluate the explosion hazard of the battery based on A, B, C, and D using the analytic hierarchy process.

10. The method for testing the explosion power of a lithium-ion battery according to claim 9, wherein, In the fifth step, weight division is performed on the shock wave pressure, light intensity, temperature, and sound intensity, which are respectively denoted as E, F, G, and H, and E + F + G + H = 100%; define the battery explosion hazard index X, then X = A * E + B * F + C * G + D * H. The larger X is, the higher the comprehensive hazard of the battery explosion indicates.

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